Brush-holder.



, PATENTBD MAR.l 24, 1908. E, B. HOWELL. BRUSH HOLDER.

APPLICATION `FILED TU NB. 1906.

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with a spring comprising a resilient member UNITED STATES PATENT OFFICE.

FRED B. HOWELL, OF SOHENECTADY, NEWy YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

BRUSH-HOLDER.

Specification of Letters Patent.

Patented March 24, 1908.

Application led June 4, 1906. Serial No. 320,036.

To all whom it'mai/ concern:

Be it known that I, FRED B. HOWELL, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Brush Holders, of which the following is a specification.

The object of my present invention is to improve the operation. and prolong the effective life of springs such as tension springs of the brush-holders employed in dynamoelectric machines.l

In employing my invention in connection formed into a helix, I place between adjacent turns'of the helix, a diaphragm or partition shield formed of some material other than that of which the resilient member is composed.l For instance, when the helical spring is formed of steel the interposed material may be copper or brass. This interposed material may advantageously be formed of a strip of sheet copper or brass bent into a helix of the same pitch as the spring proper, the two helices being threaded together. IVith this arrangement the adjacent sides of adjacent turns of the spring proper are separated by the corresponding turns of the copper or brass helix. As a result, the adjacent turns of the spring are held out of contact with each other and consequently cannot rust together. The use of my invention has been found in extensive and actual practice to be highly advantageous.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification.

For abetter understanding of my invention and the advantages possessed by it, reference may be had to the accompanying drawings and descriptive matter in which I have illustrated and described my invention as employed in a brush-holder of a well known type.

In the drawings, Figure l. is an elevation partly broken away and in section ofabrushholder and its support, and Fig. 2 is a sectional view on the line 2-2 of Fig. l.

In the drawings, l represents the brushholder support of a railway motor to which is secured the brush-holder frame 2. In the brush-holder frame 2 is secured a rivet or bolt 3 on which is journaled a pivoted brush follower member 4. The follower member 4 in the form shown is provided with a resilient p art which engages the upper end of a carbon brush 6 mounted in a box or passageway formed in the frame 2. It will be understood that the ends remote from the port 5 of the brush 6 engages the surface of the commutator indicated by dotted line 7.

The follower 4 is provided with a cylindrical portion surrounding the rivet 3, the exterior of which is provided with axially extending ribs 3. A spring member S, which may be formed of any suitable material, such as a rod or bar of tempered steel, has its body formed into a helix which surrounds the ribs 3. One end 9 of the spring is secured in any suitable manner to the frame 2, the other end 10 is secured to the follower 4. It will be understood that in the position shown in Fig. l the spring is under tension in such a manner as to tend to move the brush 6 toward the commutator 7. A strip of suitable not readily rusting or corrodible material, such as sheet copper or brass is formed into a helix, the internal ydiameter of which is approximately equal to the internal diameter of the portion of the spring 8 and is threaded into the helical portion of the spring so that each adjacent pair of turns of the springs 8 are separated by one layer of the helix ll. This prevents adjacent turns of the helical spring from rusting together, which otherwise is apt to occur and has been found to be injurious in practice, since it hastens the destruction of the spring and in creases and makes uncertain the frictional resistance to the relative movements between adjacent turns.

The use of my invention in connection With brush-holder springs by avoiding the troubles referred to has been found highly advantageous in practice, since it is essential that such springs be reliable in operation and maintain their original sensitiveness.

While the form of my invention disclosed has been found in commercial practice to be highly satisfactory it will be understood by all those skilled in the art, that changes may be made in it without departing from the spirit of my invention, and that my invention is not limited in all of its aspects to the particular embodiment disclosed.

What I claim as new, and desire to secure by Letters Patent of the United States, is,-

l. In a brush-holder, a tension spring comprising a helical body portion, `and a helical separator threaded into it, so that the turns of the spring and the separator lie side by side and are free to move relatively to one another.

2. In combination, a helical spring formed of steel, and a helix of a different metal having its turns threaded into the turns of said spring so as to form a separator, the turns of the spring and the separator lying side by side and being free to move relatively to one another.

3. In a brush-holder, a follower member pivoted to turn about an axis, said follower member having a portion cylindrical with said axis, a steel tension spring having a helical portion surrounding said cylindrical portion, and a strip of brass bent edgewise into a helix, the turns of said strip being located between the turns of the spring whereby each adjacent pair of turns of the spring are separated by the strip and the strip and spring are free to move relatively to one another.

4. In combination, a tempered steel rod formed into a helix, and a partition of nonrusting material separating adjacent turns of said helix, so that the turns of the rod and the partition lie side by side and are free to move relatively to one another.

In witness whereof, I have hereunto set my hand this 2nd day of June, 1906.

v FRED B. HOWELL.

Witnesses:

BENJAMIN B. HULL, HELEN OREORD. 

